Inert, non-porous granules for flow control in a plug flow reactor

Abstract

Process of enzymatically converting glucose to fructose wherein a glucose-containing solution is passed, under specific conditions, through a bed composed of an immobilized glucose isomerase in a fine, particulate form and non-porous beads or granular inert material such as polystyrene beads. The porous beads and granular inert material comprise between 40% and about 75% of the bed by volume. The bead's presence exerts a buoyant effect which prevents bed packing and promotes desirable flow patterns with no observable channelling. This helps to minimize the formation of undesired or undesirable carbohydrates such as psicose.

What is claimed is: 
     
       1. A process for the enzymatic isomerization of dextrose to levulose that comprises passing a solution containing dextrose through a bed comprising: a. a particulate enzyme preparation that is characterized by the ability to isomerize dextrose to levulose; and   b. substantially inert, non-porous beads having a lower specific gravity than the solution containing dextrose, distributed substantially uniformly in the bed, to space apart the particles of the enzyme preparation and exert a buoyant action and to establish the flow pattern in the bed.   
     
     
       2. A process in accordance with claim 1, wherein the particulate enzyme preparation comprises cells of a Streptomyces microorganism. 
     
     
       3. A process in accordance with claim 1 wherein the enzyme preparation comprises a dextrose isomerase that is immobilized on a particulate inorganic material. 
     
     
       4. A process in accordance with claim 1 wherein the enzyme preparation comprises a dextrose isomerase that is adsorbed on particles of basic magnesium carbonate. 
     
     
       5. A process in accordance with claim 1, wherein the beads are polystyrene beads. 
     
     
       6. A process for the enzymatic isomerization of dextrose to levulose that comprises passing a solution containing dextrose at a pH in the range of from about 6 to about 9, and at a temperature in the range from about 20°C to about 80°C through a bed in a confined reaction zone comprising: a. a particulate enzyme preparation that is characterized by the ability to isomerize dextrose to levulose; and   b. substantially inert, non-porous beads having a lower specific gravity than the solution containing dextrose, distributed substantially uniformly in the bed to space apart the particles of the enzyme preparation and exert a buoyant action and to establish the flow pattern in the bed.   
     
     
       7. A process in accordance with claim 6, wherein the beads are polystyrene beads. 
     
     
       8. A process in accordance with claim 6 wherein the enzyme preparation comprises a dextrose isomerase that is immobilized on DEAE cellulose. 
     
     
       9. A process in accordance with claim 6 comprising forming the bed with beads that form from about 40 to about 75% of the bed by volume. 
     
     
       10. A process in accordance with claim 9 wherein the enzyme preparation comprises cells of a Streptomyces microorganism. 
     
     
       11. A process in accordance with claim 9 wherein the enzyme preparation comprises a dextrose isomerase that is immobilized on a particulate inorganic carrier material. 
     
     
       12. A process in accordance with claim 9 comprising maintaining a superatmospheric pressure drop through the bed. 
     
     
       13. A process for the enzymatic isomerization of dextrose to levulose comprising the steps of; a. passing a solution containing dextrose at a pH in the range of about 6 to about 9, and a temperature in the range of about 50°C to about 80°C, through a bed in a confined reaction zone, said bed comprising: i. a dextrose isomerase that is immobilized on DEAE cellulose, and   ii. non-porous polystyrene beads that have a lower specific gravity than said solution containing dextrose, said beads being generally spherical and having a mesh size in the range -18 +50, U.S. Standard Sieve, to space apart the immobilized dextrose isomerase and to establish the flow pattern in the bed; and     b. recovering a levulose bearing solution as the effluent.